1. Field of the Invention
This invention relates generally to devices that hold hinged doors open in preselected positions, and more particularly relates to a device that holds vehicle doors, trunk lids or hoods in any preselected open position.
2. Description of the Prior Art
Car doors are notorious for slamming shut at the worst of times; fingers have been smashed, knees have been bruised, and so on. Hoods and trunk lids have also been known to slam shut at the most inopportune times.
Creative individuals have turned their attention to the problem and have developed a numer of solutions.
For example, U.S. Pat. No. 2,005,457, issued June 18, 1935 to Dubitsky and others, discloses a doorcheck for releasably holding a door in a fully open position.
U.S. Pat. No. 2,044,903 issued June 23, 1936 to Grieshaber, discloses an automobile door control with a door closing link which closes the door under action of a spring controlled by a dash pot.
A 1965 U.S. Pat. No. 3,212,122, to Flint, discloses a hydraulic hold open device for doors.
An electrically controlled shock absorber system is shown in U.S. Pat. No. 3,321,210 to Delchev (1967).
A magnetic hold-open device that employs an electromagnet that holds a door open when the magnet is energized and which releases the door when the magnet is de-energized is shown in a 1968 patent to Petersen, U.S. Pat. No. 3,415,562.
U.S. Pat. No. 3,852,846, awarded in 1974 to Slaybaugh, discloses a door hold open attachment for a door check; it features a wholly enclosed valve operating armature.
U.S. Pat. No. 4,102,004 to Nagese (1978) discloses a device for controlling the opening or closing speed of a door; it includes a piston and piston rod assembly slideably positioned in the inner tube of a dual tube hydraulic cylinder.
The prior art neither teaches nor suggests that a hydro-magnetic means could be employed to control the movement of a ball valve in a door hold open device.